QWidget #back_widget
{
    border-radius: 9px;
}

#window_title
{
    background-color: red;
    border-top-left-radius: 9px;
    border-top-right-radius: 9px;
}

#login_widget, #register_widget
{
    background-color: green;
    border-bottom-left-radius: 9px;
    border-bottom-right-radius: 9px;
}

#btn_max, #btn_min, #btn_setting, #btn_close
{
    background-color: transparent;
    border: none;
    border-radius: 4px;
}

#btn_max:hover, #btn_min:hover, #btn_setting:hover, #btn_close:hover
{
    background-color: lightgreen;
}

#btn_max:pressed, #btn_min:pressed, #btn_setting:pressed, #btn_close:pressed
{
    background-color: transparent;
}

#line_login
{
    border-radius: 3px;
    min-height: 25px;
}